What price absolute control over the most resistant populace in the world?
3,000 dead and few billion in damages?
I do not think they DID do it... but I would not put it past them.
They allowed the terrorists to walk into our country.
They failed to pursue leads concerning the terrorists (the Phoenix memo and Agent Rowley's memo)
They created a mindset of "don't resist" that allowed the terrorists to take control of the planes.
They banned Free men and women from bearing arms aboard planes, thus ensuring that terrorists would be able to hijack the aircraft.
I don't think the gov't planned the fine details, but they certainly created an environment where the terrorists could easily suceed. It's just like if the warden releases 100 felons from a prison. Does the warden know the details of when/where/how, and which felons will commit crimes? Of course not. But the warden does that crimes will invariably be committed.